An unmanned aerial vehicle (UAV), commonly known as a drone is an aircraft without a human pilot aboard. Its flight is controlled either autonomously by onboard computers or by remote control of a pilot on the ground or in another vehicle. Smaller and lighter weight Unmanned Aerial Vehicles (UAVs) and drones are increasingly being used for many applications such as but not limited to intelligence and acrobatic maneuvers applications. Some of the small UAVs may also be able to be collapsible and carried by the user within a small bag when the UAV is not in used. To increase capabilities of these aircrafts, lighter weight, more aerodynamic and small antennas are required.
A patch antenna (also known as a rectangular microstrip antenna) is a type of radio antenna with a low profile, which can be mounted on a flat surface. A typical patch antenna consists of a flat rectangular sheet or “patch” of metal which are used as radiating element, mounted over a larger sheet of metal called a ground plane. A coaxial cable extends through the ground plane at a selected location and the center pin of the coaxial cable is connected to the radiating element. The assembly is usually contained inside a plastic radome, which protects the antenna structure from damage. Patch antennas are simple to fabricate and easy to modify and customize A patch antenna is usually constructed on a dielectric substrate.
The Planar Inverted-F antenna (PIFA) is a type of patch antenna and is increasingly used in the mobile phone market. The antenna is resonant at a quarter-wavelength. This antenna resembles an inverted F, which explains the PIFA name. The Planar Inverted-F Antenna is popular because it has a low profile and an omnidirectional electromagnetic pattern. For further reducing the length of the PIFA antenna it's common to use a capacitive loading in PIFA antennas. In this technique, a capacitance is added to the PIFA antenna, between the feed point and the open edge.
U.S. Pat. No. 4,896,160 discloses an airborne surveillance platform utilizes a low aspect ratio delta-shaped aircraft having a radar-transparent hull. The antenna is located within, and stationary relative to, the hull. The antenna comprises planar or linear phased arrays arranged to scan in a continuous pattern in all azimuthal directions. Planar phased arrays can be arranged to scan in a continuous pattern in the range from zenith to nadir or in portions of that range.
U.S. Pat. No. 6,452,537 discloses a system and method for scanning through a 360 DEG azimuth by a surveillance radar antenna. The method includes driving at slow speed, the radar antenna including two electronic scanning antennas installed back to back, simultaneously controlling the electronic aiming of each of the two electronic scanning antenna, switching the microwave signal sent alternatively between the two electronic scanning antennas and, before each rotation of the radar beam, initializing the electronic aiming of each of the two elementary electronic scanning antenna at a determined angle. The radar system includes the radar antenna with the two elementary electronic scanning antennas and an aiming computer.
US2012267472 discloses a sensor/emitter arrangement integrated into the fuselage structure of a specially designed air vehicle, in which the air vehicle is configured for optimizing operation of the sensor/emitter arrangement with respect to at least azimuthal lines of sight radiating along a azimuthal reference plane of the air vehicle. The azimuthal reference plane intersects the air vehicle fuselage. The fuselage can be formed with a plurality of oblate cross-sections that facilitate maximizing the room available for a sensor/emitter array that is elongated along an elongate axis that may be aligned with the azimuthal reference plane. One or more such elongate axes may be inclines to the longitudinal (roll) axis and the pitch axis of the air vehicle. The air vehicle may have a blunt aft end incorporating an elongate aft-facing sensor/emitter array.
WO2009049595 discloses a double-lobe antenna system for passive Electronic Support Measures (ESM) sensors having a large bandwidth, it is proposed that two identical antennas having a corresponding bandwidth are disposed back to back and that a reflector is provided for bundling and deflecting the lobe of the rear antenna. The double-lobe antenna system having a wide and a narrow lobe has the same bandwidth for each lobe, has a simple, robust, and compact design, and the wide lobe can completely surround the narrow lobe.
One object of the present invention is to provide an air data terminal (ADT) that include light weight and small air data antenna(s) located within the body of a UAV. The body of the UAV is electromagnetically transparent and acts a as an antenna radome.
Yet another object of the present invention is to provide one or more small and lightweight ADT antenna located within the body of the UAV and having full antenna coverage at one or more predetermined frequency bandwidths.
Yet another object of the present invention is to provide one or more small and lightweight ADT antenna located within the body of the UAV and having full antenna coverage, to ensure proper data link to ground station, even when the UAV is doing acrobatic and sharp flight maneuvers.
Yet another object of the present invention is to provide one or more small and lightweight ADT antenna which can be easily assembled within the body of a UAV and can be also reassembled from the UAV body.